The preset invention relates to a new variant of the Der p 2 allergen of house dust mites and uses thereof.
It has long been recognized that allergy to house dust mites is a cause of many diseases such as asthma, rhinitis, sinusitis, eczema, allergic dermatitis, anaphylaxis, conjunctivitis, and/or angioedema[1]. Specifically, Dermatophagoides pteronyssinus is one of the major species of house dust mites, and many studies have been performed to identify the allergens it produces. In this regard, Der p 2 has been recognized as a representative allergen produced by D. pteronyssinus. More than 80% of allergic patients react with Der p 2[3, 4].
Der p 2 exhibits long term stability in natural conditions[6] and is resistant to heat, pH, and various chemical denaturing treatments[7]. The three-dimensional structure of Der p 2 has been determined by NMR[8] and X-ray crystallography[9]. In particular, Der p 2 exhibits the immunoglobulin (Ig)-fold structure with two anti-parallel β-sheets. In addition, Der p 2 lacks the inter-sheet disulphide bond that links the strands B and F in the Ig-like domains; instead three disulphide linkages between residues 8 and 119, 21 and 27, and 73 and 78 are present. Moreover, the disulphide bond between residues 8 and 119 links the strands A′ and G′ together, and the other two disulphide bonds are located at the loop regions.
Der p 2 cDNA sequences have been identified, and the deduced amino acid sequences reveal that Der p 2 has 146 amino acid residues with a signal peptide of 17 residues. In addition, it is found that a significant degree of polymorphism exists in the DNA sequences of Der p 2[10, 11]. To date, there have been identified eight Der p 2 variants each of which has unique amino acid substitutions at the polymorphism residues[12]. They are useful in the study of immunopathogenesis of mite allergy and the development of reagents for diagnosis and treatment of mite allergy.